> **Key takeaway:**  ☞   The renaming of "Ledger Live" to "Ledger Wallet" and\
>      "wallet" (in the hardware sense) to "signer" is still in progress.\
>      This page may contain legacy references that will be updated.

# Using the Exchange Module in Wallet API Core Client

The Exchange Module facilitates various exchange operations such as starting the exchange process, completing swap, sell, and fund transactions using .

## Exchange Module Overview

Access the Exchange module via `walletApiClient.exchange`.

### Methods:

#### 1. Start Exchange

Start the exchange process by generating a nonce on Ledger device. This method is typically called before completing the exchange process.

```javascript
walletApiClient.exchange.start(exchangeType: 'SWAP' | 'SELL' | 'FUND'): Promise<{ transactionId: string }>
```

**Parameters**:

- `exchangeType` (required): A string specifying the type of exchange operation (`"SWAP"`, `"SELL"`, or `"FUND"`).

**Returns**: A promise that resolves with an object containing the `transactionId` which is used to complete the exchange process.

[**Required permission**:](https://developers.ledger.com/docs/ledger-live/discover/guides/wallet-api/appendix/manifest#permissions)
`exchange.start`

##### Example:

```javascript
async function startExchange(walletApiClient, exchangeType) {
  try {
    const { transactionId } = await walletApiClient.exchange.start(
      exchangeType
    );
    console.log("Transaction ID:", transactionId);
  } catch (error) {
    console.error("Error starting exchange:", error);
  }
}
```

#### 2. Complete Exchange

Complete an exchange process (swap, sell, or fund) by passing the exchange content and its signature.

```javascript
walletApiClient.exchange.complete(params: {
  provider: string,
  fromAccountId: string,
  rawTransaction: RawTransaction,
  hexBinaryPayload: string,
  hexSignature: string,
  feeStrategy: 'SLOW' | 'MEDIUM' | 'FAST',
  exchangeType: 'SWAP' | 'SELL' | 'FUND',
  toAccountId?: string,
  swapId?: string,
  rate?: number,
  tokenCurrency?: string,
}): Promise<{ transactionHash: string }>
```

**Parameters**: An object containing:

- `provider` (required): A string used to verify the signature.
- `fromAccountId` (required): Identifier of the account used as a source for the transaction.
- `rawTransaction` (required): A RawTransaction object containing the transaction details.
- `hexBinaryPayload` (required): Hexadecimal string representing the blueprint of the data that will be allowed for signing.
- `hexSignature` (required): Hexadecimal string ensuring the source of the payload.
- `feeStrategy` (required): A string representing the fee strategy (`"SLOW"`, `"MEDIUM"`, or `"FAST"`).
- `exchangeType` (required): A string specifying the type of exchange operation (`"SWAP"`, `"SELL"`, or `"FUND"`).
- `toAccountId` (optional): Identifier of the account used as a destination (required for `"SWAP"`).
- `swapId` (optional): Identifier of the backend swap used (required for `"SWAP"`).
- `rate` (optional): Swap rate used in the transaction (required for `"SWAP"`).
- `tokenCurrency` (optional): Swap tokenCurrency is used when we want point a new token, as id does not exists in wallet-api (optional for `"SWAP"` and `"FUND"`).

**Returns**: A promise that resolves with an object containing the `transactionHash` of the broadcasted transaction.

[**Required permission**:](https://developers.ledger.com/docs/ledger-live/discover/guides/wallet-api/appendix/manifest#permissions)
`exchange.complete`

##### Example:

```javascript
async function completeExchange(walletApiClient, exchangeParams) {
  try {
    const { transactionHash } = await walletApiClient.exchange.complete(
      exchangeParams
    );
    console.log("Transaction Hash:", transactionHash);
  } catch (error) {
    console.error("Error completing exchange:", error);
  }
}
```

## Handling Errors

Make sure to handle errors gracefully and provide appropriate feedback to the user. Additionally, always remember to disconnect the `WindowMessageTransport` when you're done interacting with the  API to free up resources.